Field of the Invention
The present invention relates to a power supply system, and especially relates to a power supply system with a main power output-feedback and a standby power output-feedback.
Description of the Related Art
FIG. 1 shows a circuit diagram of a related art power supply system. A power supply system 1 comprises a power supply apparatus 10 and an electric power feedback control module 12. The power supply apparatus 10 comprises a main power output terminal Vo1 and a standby power output terminal Vo2. The electric power feedback control module 12 is electrically connected to the main power output terminal Vo1. The main power output terminal Vo1 and the standby power output terminal Vo2 are electrically connected to a power conversion system PS respectively. The main power output terminal Vo1 and the standby power output terminal Vo2 output electric power to the power conversion system PS for a working status and a standby status respectively. In another word, the main power output terminal Vo1 of the power supply apparatus 10 outputs electric power (for example, a direct current power 12 volts) to the power conversion system PS when the power conversion system PS is in the working status. The standby power output terminal Vo2 of the power supply apparatus 10 outputs electric power to the power conversion system PS when the power conversion system PS is in the standby status for energy saving.
The electric power feedback control module 12 comprises a controller 120, an isolation unit 122 and a voltage compensating unit 124. The voltage compensating unit 124 is electrically connected to the main power output terminal Vo1. The isolation unit 122 is electrically connected to the voltage compensating unit 124 and the controller 120. The controller 120 is electrically connected to the power supply apparatus 10.
The voltage compensating unit 124 of the electric power feedback control module 12 detects an output electric power of the main power output terminal Vo1. The voltage compensating unit 124 outputs a signal to the isolation unit 122 if an output voltage value of the main power output terminal Vo1 is lower than a predetermined voltage value. The controller 120 is configured to control the power supply apparatus 10 to increase the output electric power of the main power output terminal Vo1 according to the signal mentioned above.
The electric power feedback control module 12 mainly detects the voltage value of the output electric power of the main power output terminal Vo1. The electric power feedback control module 12 informs the controller 120 to control the power supply apparatus 10 to decrease or increase the voltage value of the output electric power of the main power output terminal Vo1 if the voltage value mentioned above is higher or lower than the predetermined voltage value. In another word, the electric power feedback control module 12 monitors the voltage value of the output electric power of the main power output terminal Vo1 when the power conversion system PS is in the working status, so that the voltage value mentioned above is maintained in a specific range.
However, a voltage value of the output electric power of the standby power output terminal Vo2 cannot feedback to the power supply apparatus 10 when the power conversion system PS is in the standby status. The output electric power of the standby power output terminal Vo2 is enough for the power conversion system PS when the power conversion system PS is in the standby status and with a very light load. However, the voltage value of the output electric power of the standby power output terminal Vo2 is decreased when the power conversion system PS is in the standby status and with a conventional load (for example, a microprocessor of the power conversion system PS is operating or the power conversion system PS is supplying power to an electronic device, such as a cellphone). Therefore, the output electric power of the standby power output terminal Vo2 may be not enough for the power conversion system PS to maintain in the standby status.